Tuner construction



Feb. 12, 1952 I R. ROMERO 2,585,844

' TUNER CONSTRUCTION Filed Se t. 27, 1950 7 I27 (20 F/Li 5:

27 P05537- Eomseo ma/em. 7 5 WWII/ ,7 4m

Patented Feb. 12, 1952 TUNER CONSTRUCTION Robert Romero, Forest Hills,N. Y., assignor to Leonard Electric Products Corp., Brooklyn, N. Y., acorporation of New York Application September 2'7, 1950, Serial No.186,941

3 Claims.

The present invention relates to improvements in television tuners, andmore particularly to structure for associating a vernier condensertherewith for the local oscillator thereof.

Tuners herein concerned with, are of the class having variousinductances housed within a casing with means to alter the inductance incircuit, operated by the turning of a shaft. Also, the verniercondensers are of the type which are adjusted by the turning of a shaft.In a tuner combined with such condenser, it is practical that one oftheir respective shafts shall be tubular so that the other lie within itin concentric relation; the outer shaft serving as a bearing for theinner. Where such pair of shafts are together for more than just a veryfew inches in length, any slight variance of the inner shaft from truestraightness would render free turning thereof difficult, and evennormally, the friction between such shafts is appreciable.

Further, mounting the shafts, presents various mechanical difliculties,since it is desired that the casing walls shall support them andconstruction should be such to afford easy assembly and economicalmanufacture.

It is therefore an object of this invention to provide a novel andimproved construction in concentrically associated shafts of thecharacter mentioned, which is free of undue friction between the shaftsand permits easy turning of both of them although there be a variancefrom true straightness in either of them.

Another object thereof is to provide a novel and improved constructionin concentrically associated shafts of the nature set forth, whichpermits proper and easy assembly with the tuners casing.

A further object of this invention is to use a vernier condenser ofnovel and improved construction and so associate it with the casing ofthe tuner, as to shield the condenser in order to avoid interferencewith other circuits, ordinarily occasioned in condenser operation, andto better stabilize the local circuit.

Another object hereof is to provide novel and improved constructions intuner and vernier condenser combinations of the character described,which are convenient and economical in manufacture and efficient incarrying out the purposes for which they are designed.

Other objects and advantages will become apparent as this disclosureproceeds.

In the accompanying drawings forming part of this specification, similarcharacters of reference indicate corresponding parts in all the views.

Fig. 1 shows a television tuner embodying the teachings of thisinvention. The view here shown is fragmentary, partly in section, and istaken looking into the casing, which would be a front view of the casingas particularly is shown in Fig. 4.

Fig. 2 is a side view of Fig. 1, with part of the casing wall shownbroken away in order to expose the vernier condenser I provide herein.

Fig. 3 is a diagrammatic view of the electrical circuit portion whichincludes said condenser and tuner.

Fig. 4 is an exploded view showing in perspective, several of thecomponents included in the embodiment shown in Fig. 1.

Fig. 5 is a magnified, fragmentary sectional view taken through thetubular shaft at lines 5-5 in Fig. 4, and also showing a portion of theinner shaft.

In the preferred embodiment shown in the drawings, the numeral I 5denotes the metal casing for the drum indicated generally by the numerall6, which is securely mounted in any suitable manner on the inner shaftH. The outer shaft I8 is tubular, and at one end which is mounted on thecasing, is formed with the annular channel l9 between shoulders 20 and2|. A small plate 22 has a hole 23, whereby it is set on shoulder 20,rather loosely. A metal plate 24, whose periphery 24' is a spiral withrespect to the hole 25, is secured on the shoulder 2|. The ends of theshafts are machined with flats as at I1 and I8 respectively, for themounting of proper hand knobs not shown, but well known in the art.

It has heretofore been the practice that the shafts be in rotatablecontact fit along the entire length of the tubular shaft l8. This hasproven objectionable as explained. I therefore take a piece of tubularstock whose bore is larger than the diameter of the inner shaft I1, andbefore machining its ends exteriorally as shown, I swage a comparativelyshort region at each end of the tube to bring the bore down in such endregions to a size which is a little less than the diameter of the innershaft. Then I pass a reamer through the tube so that both ends havebores like 26, affording suitable bearing fit for the inner shaft I'l,while in the remainder of the tubular shaft l8 there is the annularclearance 21, when the shafts are assembled.

The tuner l6 may be of the type including a plurality of insulativestrips 28, arranged as staves carried by end plates as 29. On the undersurface of each of these strips 28, are carried inductance coils 30 ofpredetermined value, whose terminals are connected to contact buttons as3|, which when the drum is turned, come into contact with brushes 32,thereby bringing desired coils in circuit. Several of these partsmentioned are not shown in Figs. 1 and 2, because they are well known inthis art, and do not concern this invention. To properly position thedrum at each of its operating positions, an end plate 29 may be providedwith suitably spaced notches 33, for selective engagement by a springdetent 34.

The vernier condenser which I use, employs the spiral-shaped platemember 24, and a pair of spaced metal buttons 35 and 36 on a piece 31 ofinsulative material secured within the casing by means of a bracket 38.mounted as will be explained, the plate member 24 will be positioned ina plane parallel to the plane of the faces of the metal buttons 35 and36, and spaced therefrom a predetermined distance. Said plate member 24has no electrical connections thereto. It is said button members 35 and36, which are respectively electrically connected to the terminals ofthe inductance 30 in circuit, by means of the brushes 32; said buttonsbeing respectively connected electrically to said brushes.

The casing I is provided with an open bearing 39 to receive the innershaft I! in annular channel 40, and in its opposite wall with an openbearing 4| to receive the outer shaft H3 in annular channel l9. Withtheir heads exterior the casing, screws 42 pass loose through holes 43in plate member 22, and threadedly engage the casing wall in thethreaded holes 44. A stiff spring wire 45 is positioned as shown in Fig.2, to engage the shanks of the screws 42 on one side and the tubularshaft l8 on the other side, so that said shaft is maintained in contactwith the halfround edge 4| of the bearing 4|. Similar spring and itsengagement means may be provided to maintain the inner shaft I! incontact with the half-round edge 39. It is evident that removal of thespring means mentioned and the screws 42, permits removal of the shaftsI7 and I8 with the components they carry, from the casing IS. Thecondenser indicated generally by the numeral 46, being positioned withinthe metal casing, is thereby shielded against causing objectionabledisturbances which may be occasioned by its operation.

It is to be noted that the plate 22 serves particularly to preventdamage to the drum l6 and the casing l5, which would be occasioned ifaccidently a severe force were applied at the forward milled ends of theshafts in a direction outwardly of the open bearing 4 I.

It is also to be noted that the foregoing man- When the shaft I8 is nerof construction and association of condenser and casing, has proven anaid in materially reducing electrical noise.

This invention is capable of numerous forms and various applicationswithout departing from the essential features herein disclosed. It istherefore intended and desired that the embodiment herein shall bedeemed illustrative and not restrictive and that the patent shall coverall patentable novelty herein set forth; reference being had to thefollowing claims rather than to the specific description herein toindicate the scope of this invention.

I claim:

1. In an apparatus of the character described, the combination of acontainer having an open mouth, an elongated tubular shaft having anexterior annular channel whereby a reduced portion exists intermediatethe ends of said tubular shaft; said container having an open bearing ina wall thereof of a size to admit said reduced portion whereby an end ofthe tubular shaft is positioned through said mouth in a lateraldirection, a detachable plate adapted to be mounted on the container toclose said bearing; said plate being carried loosely on the tubularshaft, spring means on the container, pressing the tubular shaft in alateral direction, an inner shaft positioned through the tubular shaftand extending outwardly from each end thereof and means to hold theshafts against relative longitudinal movement; the walls of the channelbeing substantially in contact with the respective surfaces of the wallof the container; the tubular shaft being rotatable in said bearing andthe inner shaft being rotatable with respect to the tubular shaft.

2. An apparatus as defined in claim 1, wherein the tubular shaft has areduced bore at each end portion thereof serving as bearingsrespectively for the inner shaft.

3. An apparatus as defined in claim 1, wherein an annular space existsbetween the shafts within and intermediate the ends of the tubularshaft.

ROBERT ROMERO.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,608,526 Potter Nov. 30, 19261,906,857 Heyne et a1 May 2, 1933 2,496,183 Thias et al. Jan. 31, 19502,532,263 Silvey Nov. 28, 1950

